Go to the nearest army surplus shop and get one or two (or more) army crates. They come in many size (the biggest is 1,20m in length), are not that expensive regarding the service they offer and may even be salvaged.

Don't forget to label your stuff properly.

Get Small ammo cases. (they go as low as 5€, add coolness points, are mostly waterproof and are tough as hell beside being rock'n'roll)